Eh, I wouldn't really know. DBZ was an anime I could never get into. It came at about the same time for me as other things, but Pokemon and YuGiOh struck the right chords where DBz was just kind of... meh. But yeah, asking if Goku could beat the Guardians would be like asking "Can an elderly man beat Hercules in a fist fight?". There's no real point the question other than Goku fans trying to rub their Goku infused egos and going "Yeah, our fandom is the best" with their hands down their pants.